Request multiple S3 files into one request - http

Is there a way to get multiple files from S3 (or any CDN) in one request?
For example, I have four files on S3:
example.com/cdn/one.js
example.com/cdn/two.js
example.com/cdn/three.js
example.com/cdn/four.js
I would like to be able to request any combination of them at a time. I currently have to include them separately:
<script src="example.com/cdn/one.js" />
<script src="example.com/cdn/two.js" />
But I would like to include them as one request:
example.com/cdn/code.js?one&two
I've considered combining the needed combinations into single files, but there will be way too many combinations for that to be realistic. I've also considered combining all of them into one file, but that would be ridiculously large.

First of all: Your question is more a JS thing than related to S3 / CDNs in general. And to answer your question: You can't "combine" them in one http request.
If you don't want to concatenate and minify them you should take a look at RequireJS, which could handle loading of your scripts – it's async and won't block the browser from rendering.
This is a really great article about async loading: css-tricks.com - Thinking Async which will give you a better insight.
EDIT after comment:
You can in fact use PHP to concatenate & minify your JS files on the fly, but this will put additional load on your server and you'll loose the benefits you get from a CDN … Another approach would be using a build system, which packs everything before it goes into production.
For further information on this topic take a look at the following links:
PHP5 - minify
PHP5 - Assetic
How do I concatenate JavaScript files into one file?
To do on the fly minifaction on your dev system (if it's a Mac) you may want to try CodeKit.

Here is one way you could do that (assuming you just use one&two&three and note file=one&file=two&file=3):
function getJs() {
var url = window.location.toString();
var query = url.split("?");
var params = query.split("&");
// iterate through array of params and write JS
for (i=0; i<params.length; i++) {
var name = params[i] + ".js";
document.write("<script defer language='javascript' type='text/javascript' src='" + name + "'><\/sc" + "ript>");
}
}
This should load after the page is loaded. Then in in your HTML perhaps. I haven't tested this but should be what you're looking for I reckon.

Related

Django Static Files Won't Reload On Firefox [duplicate]

I have noticed that some browsers (in particular, Firefox and Opera) are very zealous in using cached copies of .css and .js files, even between browser sessions. This leads to a problem when you update one of these files, but the user's browser keeps on using the cached copy.
What is the most elegant way of forcing the user's browser to reload the file when it has changed?
Ideally, the solution would not force the browser to reload the file on every visit to the page.
I have found John Millikin's and da5id's suggestion to be useful. It turns out there is a term for this: auto-versioning.
I have posted a new answer below which is a combination of my original solution and John's suggestion.
Another idea that was suggested by SCdF would be to append a bogus query string to the file. (Some Python code, to automatically use the timestamp as a bogus query string, was submitted by pi..)
However, there is some discussion as to whether or not the browser would cache a file with a query string. (Remember, we want the browser to cache the file and use it on future visits. We only want it to fetch the file again when it has changed.)
This solution is written in PHP, but it should be easily adapted to other languages.
The original .htaccess regex can cause problems with files like json-1.3.js. The solution is to only rewrite if there are exactly 10 digits at the end. (Because 10 digits covers all timestamps from 9/9/2001 to 11/20/2286.)
First, we use the following rewrite rule in .htaccess:
RewriteEngine on
RewriteRule ^(.*)\.[\d]{10}\.(css|js)$ $1.$2 [L]
Now, we write the following PHP function:
/**
* Given a file, i.e. /css/base.css, replaces it with a string containing the
* file's mtime, i.e. /css/base.1221534296.css.
*
* #param $file The file to be loaded. Must be an absolute path (i.e.
* starting with slash).
*/
function auto_version($file)
{
if(strpos($file, '/') !== 0 || !file_exists($_SERVER['DOCUMENT_ROOT'] . $file))
return $file;
$mtime = filemtime($_SERVER['DOCUMENT_ROOT'] . $file);
return preg_replace('{\\.([^./]+)$}', ".$mtime.\$1", $file);
}
Now, wherever you include your CSS, change it from this:
<link rel="stylesheet" href="/css/base.css" type="text/css" />
To this:
<link rel="stylesheet" href="<?php echo auto_version('/css/base.css'); ?>" type="text/css" />
This way, you never have to modify the link tag again, and the user will always see the latest CSS. The browser will be able to cache the CSS file, but when you make any changes to your CSS the browser will see this as a new URL, so it won't use the cached copy.
This can also work with images, favicons, and JavaScript. Basically anything that is not dynamically generated.
Simple Client-side Technique
In general, caching is good... So there are a couple of techniques, depending on whether you're fixing the problem for yourself as you develop a website, or whether you're trying to control cache in a production environment.
General visitors to your website won't have the same experience that you're having when you're developing the site. Since the average visitor comes to the site less frequently (maybe only a few times each month, unless you're a Google or hi5 Networks), then they are less likely to have your files in cache, and that may be enough.
If you want to force a new version into the browser, you can always add a query string to the request, and bump up the version number when you make major changes:
<script src="/myJavascript.js?version=4"></script>
This will ensure that everyone gets the new file. It works because the browser looks at the URL of the file to determine whether it has a copy in cache. If your server isn't set up to do anything with the query string, it will be ignored, but the name will look like a new file to the browser.
On the other hand, if you're developing a website, you don't want to change the version number every time you save a change to your development version. That would be tedious.
So while you're developing your site, a good trick would be to automatically generate a query string parameter:
<!-- Development version: -->
<script>document.write('<script src="/myJavascript.js?dev=' + Math.floor(Math.random() * 100) + '"\><\/script>');</script>
Adding a query string to the request is a good way to version a resource, but for a simple website this may be unnecessary. And remember, caching is a good thing.
It's also worth noting that the browser isn't necessarily stingy about keeping files in cache. Browsers have policies for this sort of thing, and they are usually playing by the rules laid down in the HTTP specification. When a browser makes a request to a server, part of the response is an Expires header... a date which tells the browser how long it should be kept in cache. The next time the browser comes across a request for the same file, it sees that it has a copy in cache and looks to the Expires date to decide whether it should be used.
So believe it or not, it's actually your server that is making that browser cache so persistent. You could adjust your server settings and change the Expires headers, but the little technique I've written above is probably a much simpler way for you to go about it. Since caching is good, you usually want to set that date far into the future (a "Far-future Expires Header"), and use the technique described above to force a change.
If you're interested in more information on HTTP or how these requests are made, a good book is "High Performance Web Sites" by Steve Souders. It's a very good introduction to the subject.
Google's mod_pagespeed plugin for Apache will do auto-versioning for you. It's really slick.
It parses HTML on its way out of the webserver (works with PHP, Ruby on Rails, Python, static HTML -- anything) and rewrites links to CSS, JavaScript, image files so they include an id code. It serves up the files at the modified URLs with a very long cache control on them. When the files change, it automatically changes the URLs so the browser has to re-fetch them. It basically just works, without any changes to your code. It'll even minify your code on the way out too.
Instead of changing the version manually, I would recommend you use an MD5 hash of the actual CSS file.
So your URL would be something like
http://mysite.com/css/[md5_hash_here]/style.css
You could still use the rewrite rule to strip out the hash, but the advantage is that now you can set your cache policy to "cache forever", since if the URL is the same, that means that the file is unchanged.
You can then write a simple shell script that would compute the hash of the file and update your tag (you'd probably want to move it to a separate file for inclusion).
Simply run that script every time CSS changes and you're good. The browser will ONLY reload your files when they are altered. If you make an edit and then undo it, there's no pain in figuring out which version you need to return to in order for your visitors not to re-download.
I am not sure why you guys/gals are taking so much pain to implement this solution.
All you need to do if get the file's modified timestamp and append it as a querystring to the file.
In PHP I would do it as:
<link href="mycss.css?v=<?= filemtime('mycss.css') ?>" rel="stylesheet">
filemtime() is a PHP function that returns the file modified timestamp.
You can just put ?foo=1234 at the end of your CSS / JavaScript import, changing 1234 to be whatever you like. Have a look at the Stack Overflow HTML source for an example.
The idea there being that the ? parameters are discarded / ignored on the request anyway and you can change that number when you roll out a new version.
Note: There is some argument with regard to exactly how this affects caching. I believe the general gist of it is that GET requests, with or without parameters should be cachable, so the above solution should work.
However, it is down to both the web server to decide if it wants to adhere to that part of the spec and the browser the user uses, as it can just go right ahead and ask for a fresh version anyway.
I've heard this called "auto versioning". The most common method is to include the static file's modification time somewhere in the URL, and strip it out using rewrite handlers or URL configurations:
See also:
Automatic asset versioning in Django
Automatically Version Your CSS and JavaScript Files
The 30 or so existing answers are great advice for a circa 2008 website. However, when it comes to a modern, single-page application (SPA), it might be time to rethink some fundamental assumptions… specifically the idea that it is desirable for the web server to serve only the single, most recent version of a file.
Imagine you're a user that has version M of a SPA loaded into your browser:
Your CD pipeline deploys the new version N of the application onto the server
You navigate within the SPA, which sends an XMLHttpRequest (XHR) to the server to get /some.template
(Your browser hasn't refreshed the page, so you're still running version M)
The server responds with the contents of /some.template — do you want it to return version M or N of the template?
If the format of /some.template changed between versions M and N (or the file was renamed or whatever) you probably don't want version N of the template sent to the browser that's running the old version M of the parser.†
Web applications run into this issue when two conditions are met:
Resources are requested asynchronously some time after the initial page load
The application logic assumes things (that may change in future versions) about resource content
Once your application needs to serve up multiple versions in parallel, solving caching and "reloading" becomes trivial:
Install all site files into versioned directories: /v<release_tag_1>/…files…, /v<release_tag_2>/…files…
Set HTTP headers to let browsers cache files forever
(Or better yet, put everything in a CDN)
Update all <script> and <link> tags, etc. to point to that file in one of the versioned directories
That last step sounds tricky, as it could require calling a URL builder for every URL in your server-side or client-side code. Or you could just make clever use of the <base> tag and change the current version in one place.
† One way around this is to be aggressive about forcing the browser to reload everything when a new version is released. But for the sake of letting any in-progress operations to complete, it may still be easiest to support at least two versions in parallel: v-current and v-previous.
In Laravel (PHP) we can do it in the following clear and elegant way (using file modification timestamp):
<script src="{{ asset('/js/your.js?v='.filemtime('js/your.js')) }}"></script>
And similar for CSS
<link rel="stylesheet" href="{{asset('css/your.css?v='.filemtime('css/your.css'))}}">
Example HTML output (filemtime return time as as a Unix timestamp)
<link rel="stylesheet" href="assets/css/your.css?v=1577772366">
Don’t use foo.css?version=1!
Browsers aren't supposed to cache URLs with GET variables. According to http://www.thinkvitamin.com/features/webapps/serving-javascript-fast, though Internet Explorer and Firefox ignore this, Opera and Safari don't! Instead, use foo.v1234.css, and use rewrite rules to strip out the version number.
Here is a pure JavaScript solution
(function(){
// Match this timestamp with the release of your code
var lastVersioning = Date.UTC(2014, 11, 20, 2, 15, 10);
var lastCacheDateTime = localStorage.getItem('lastCacheDatetime');
if(lastCacheDateTime){
if(lastVersioning > lastCacheDateTime){
var reload = true;
}
}
localStorage.setItem('lastCacheDatetime', Date.now());
if(reload){
location.reload(true);
}
})();
The above will look for the last time the user visited your site. If the last visit was before you released new code, it uses location.reload(true) to force page refresh from server.
I usually have this as the very first script within the <head> so it's evaluated before any other content loads. If a reload needs to occurs, it's hardly noticeable to the user.
I am using local storage to store the last visit timestamp on the browser, but you can add cookies to the mix if you're looking to support older versions of IE.
The RewriteRule needs a small update for JavaScript or CSS files that contain a dot notation versioning at the end. E.g., json-1.3.js.
I added a dot negation class [^.] to the regex, so .number. is ignored.
RewriteRule ^(.*)\.[^.][\d]+\.(css|js)$ $1.$2 [L]
Interesting post. Having read all the answers here combined with the fact that I have never had any problems with "bogus" query strings (which I am unsure why everyone is so reluctant to use this) I guess the solution (which removes the need for Apache rewrite rules as in the accepted answer) is to compute a short hash of the CSS file contents (instead of the file datetime) as a bogus querystring.
This would result in the following:
<link rel="stylesheet" href="/css/base.css?[hash-here]" type="text/css" />
Of course, the datetime solutions also get the job done in the case of editing a CSS file, but I think it is about the CSS file content and not about the file datetime, so why get these mixed up?
For ASP.NET 4.5 and greater you can use script bundling.
The request http://localhost/MvcBM_time/bundles/AllMyScripts?v=r0sLDicvP58AIXN_mc3QdyVvVj5euZNzdsa2N1PKvb81 is for the bundle AllMyScripts and contains a query string pair v=r0sLDicvP58AIXN_mc3QdyVvVj5euZNzdsa2N1PKvb81. The query string v has a value token that is a unique identifier used for caching. As long as the bundle doesn't change, the ASP.NET application will request the AllMyScripts bundle using this token. If any file in the bundle changes, the ASP.NET optimization framework will generate a new token, guaranteeing that browser requests for the bundle will get the latest bundle.
There are other benefits to bundling, including increased performance on first-time page loads with minification.
For my development, I find that Chrome has a great solution.
https://superuser.com/a/512833
With developer tools open, simply long click the refresh button and let go once you hover over "Empty Cache and Hard Reload".
This is my best friend, and is a super lightweight way to get what you want!
Thanks to Kip for his perfect solution!
I extended it to use it as an Zend_view_Helper. Because my client run his page on a virtual host I also extended it for that.
/**
* Extend filepath with timestamp to force browser to
* automatically refresh them if they are updated
*
* This is based on Kip's version, but now
* also works on virtual hosts
* #link http://stackoverflow.com/questions/118884/what-is-an-elegant-way-to-force-browsers-to-reload-cached-css-js-files
*
* Usage:
* - extend your .htaccess file with
* # Route for My_View_Helper_AutoRefreshRewriter
* # which extends files with there timestamp so if these
* # are updated a automatic refresh should occur
* # RewriteRule ^(.*)\.[^.][\d]+\.(css|js)$ $1.$2 [L]
* - then use it in your view script like
* $this->headLink()->appendStylesheet( $this->autoRefreshRewriter($this->cssPath . 'default.css'));
*
*/
class My_View_Helper_AutoRefreshRewriter extends Zend_View_Helper_Abstract {
public function autoRefreshRewriter($filePath) {
if (strpos($filePath, '/') !== 0) {
// Path has no leading '/'
return $filePath;
} elseif (file_exists($_SERVER['DOCUMENT_ROOT'] . $filePath)) {
// File exists under normal path
// so build path based on this
$mtime = filemtime($_SERVER['DOCUMENT_ROOT'] . $filePath);
return preg_replace('{\\.([^./]+)$}', ".$mtime.\$1", $filePath);
} else {
// Fetch directory of index.php file (file from all others are included)
// and get only the directory
$indexFilePath = dirname(current(get_included_files()));
// Check if file exist relativ to index file
if (file_exists($indexFilePath . $filePath)) {
// Get timestamp based on this relativ path
$mtime = filemtime($indexFilePath . $filePath);
// Write generated timestamp to path
// but use old path not the relativ one
return preg_replace('{\\.([^./]+)$}', ".$mtime.\$1", $filePath);
} else {
return $filePath;
}
}
}
}
I have not found the client-side DOM approach creating the script node (or CSS) element dynamically:
<script>
var node = document.createElement("script");
node.type = "text/javascript";
node.src = 'test.js?' + Math.floor(Math.random()*999999999);
document.getElementsByTagName("head")[0].appendChild(node);
</script>
Say you have a file available at:
/styles/screen.css
You can either append a query parameter with version information onto the URI, e.g.:
/styles/screen.css?v=1234
Or you can prepend version information, e.g.:
/v/1234/styles/screen.css
IMHO, the second method is better for CSS files, because they can refer to images using relative URLs which means that if you specify a background-image like so:
body {
background-image: url('images/happy.gif');
}
Its URL will effectively be:
/v/1234/styles/images/happy.gif
This means that if you update the version number used, the server will treat this as a new resource and not use a cached version. If you base your version number on the Subversion, CVS, etc. revision this means that changes to images referenced in CSS files will be noticed. That isn't guaranteed with the first scheme, i.e. the URL images/happy.gif relative to /styles/screen.css?v=1235 is /styles/images/happy.gif which doesn't contain any version information.
I have implemented a caching solution using this technique with Java servlets and simply handle requests to /v/* with a servlet that delegates to the underlying resource (i.e. /styles/screen.css). In development mode I set caching headers that tell the client to always check the freshness of the resource with the server (this typically results in a 304 if you delegate to Tomcat's DefaultServlet and the .css, .js, etc. file hasn't changed) while in deployment mode I set headers that say "cache forever".
You could simply add some random number with the CSS and JavaScript URL like
example.css?randomNo = Math.random()
Google Chrome has the Hard Reload as well as the Empty Cache and Hard Reload option. You can click and hold the reload button (in Inspect Mode) to select one.
I recently solved this using Python. Here is the code (it should be easy to adopt to other languages):
def import_tag(pattern, name, **kw):
if name[0] == "/":
name = name[1:]
# Additional HTML attributes
attrs = ' '.join(['%s="%s"' % item for item in kw.items()])
try:
# Get the files modification time
mtime = os.stat(os.path.join('/documentroot', name)).st_mtime
include = "%s?%d" % (name, mtime)
# This is the same as sprintf(pattern, attrs, include) in other
# languages
return pattern % (attrs, include)
except:
# In case of error return the include without the added query
# parameter.
return pattern % (attrs, name)
def script(name, **kw):
return import_tag('<script %s src="/%s"></script>', name, **kw)
def stylesheet(name, **kw):
return import_tag('<link rel="stylesheet" type="text/css" %s href="/%s">', name, **kw)
This code basically appends the files time-stamp as a query parameter to the URL. The call of the following function
script("/main.css")
will result in
<link rel="stylesheet" type="text/css" href="/main.css?1221842734">
The advantage of course is that you do never have to change your HTML content again, touching the CSS file will automatically trigger a cache invalidation. It works very well and the overhead is not noticeable.
You can force a "session-wide caching" if you add the session-id as a spurious parameter of the JavaScript/CSS file:
<link rel="stylesheet" src="myStyles.css?ABCDEF12345sessionID" />
<script language="javascript" src="myCode.js?ABCDEF12345sessionID"></script>
If you want a version-wide caching, you could add some code to print the file date or similar. If you're using Java you can use a custom-tag to generate the link in an elegant way.
<link rel="stylesheet" src="myStyles.css?20080922_1020" />
<script language="javascript" src="myCode.js?20080922_1120"></script>
For ASP.NET I propose the following solution with advanced options (debug/release mode, versions):
Include JavaScript or CSS files this way:
<script type="text/javascript" src="Scripts/exampleScript<%=Global.JsPostfix%>" />
<link rel="stylesheet" type="text/css" href="Css/exampleCss<%=Global.CssPostfix%>" />
Global.JsPostfix and Global.CssPostfix are calculated by the following way in Global.asax:
protected void Application_Start(object sender, EventArgs e)
{
...
string jsVersion = ConfigurationManager.AppSettings["JsVersion"];
bool updateEveryAppStart = Convert.ToBoolean(ConfigurationManager.AppSettings["UpdateJsEveryAppStart"]);
int buildNumber = System.Reflection.Assembly.GetExecutingAssembly().GetName().Version.Revision;
JsPostfix = "";
#if !DEBUG
JsPostfix += ".min";
#endif
JsPostfix += ".js?" + jsVersion + "_" + buildNumber;
if (updateEveryAppStart)
{
Random rand = new Random();
JsPosfix += "_" + rand.Next();
}
...
}
If you're using Git and PHP, you can reload the script from the cache each time there is a change in the Git repository, using the following code:
exec('git rev-parse --verify HEAD 2> /dev/null', $gitLog);
echo ' <script src="/path/to/script.js"?v='.$gitLog[0].'></script>'.PHP_EOL;
Simply add this code where you want to do a hard reload (force the browser to reload cached CSS and JavaScript files):
$(window).load(function() {
location.reload(true);
});
Do this inside the .load, so it does not refresh like a loop.
For development: use a browser setting: for example, Chrome network tab has a disable cache option.
For production: append a unique query parameter to the request (for example, q?Date.now()) with a server-side rendering framework or pure JavaScript code.
// Pure JavaScript unique query parameter generation
//
//=== myfile.js
function hello() { console.log('hello') };
//=== end of file
<script type="text/javascript">
document.write('<script type="text/javascript" src="myfile.js?q=' + Date.now() + '">
// document.write is considered bad practice!
// We can't use hello() yet
</script>')
<script type="text/javascript">
hello();
</script>
For developers with this problem while developing and testing:
Remove caching briefly.
"keep caching consistent with the file" .. it's way too much hassle ..
Generally speaking, I don't mind loading more - even loading again files which did not change - on most projects - is practically irrelevant. While developing an application - we are mostly loading from disk, on localhost:port - so this increase in network traffic issue is not a deal breaking issue.
Most small projects are just playing around - they never end-up in production. So for them you don't need anything more...
As such if you use Chrome DevTools, you can follow this disable-caching approach like in the image below:
And if you have Firefox caching issues:
Do this only in development. You also need a mechanism to force reload for production, since your users will use old cache invalidated modules if you update your application frequently and you don't provide a dedicated cache synchronisation mechanism like the ones described in the answers above.
Yes, this information is already in previous answers, but I still needed to do a Google search to find it.
It seems all answers here suggest some sort of versioning in the naming scheme, which has its downsides.
Browsers should be well aware of what to cache and what not to cache by reading the web server's response, in particular the HTTP headers - for how long is this resource valid? Was this resource updated since I last retrieved it? etc.
If things are configured 'correctly', just updating the files of your application should (at some point) refresh the browser's caches. You can for example configure your web server to tell the browser to never cache files (which is a bad idea).
A more in-depth explanation of how that works is in How Web Caches Work.
Just use server-side code to add the date of the file... that way it will be cached and only reloaded when the file changes.
In ASP.NET:
<link rel="stylesheet" href="~/css/custom.css?d=#(System.Text.RegularExpressions.Regex.Replace(File.GetLastWriteTime(Server.MapPath("~/css/custom.css")).ToString(),"[^0-9]", ""))" />
<script type="text/javascript" src="~/js/custom.js?d=#(System.Text.RegularExpressions.Regex.Replace(File.GetLastWriteTime(Server.MapPath("~/js/custom.js")).ToString(),"[^0-9]", ""))"></script>
This can be simplified to:
<script src="<%= Page.ResolveClientUrlUnique("~/js/custom.js") %>" type="text/javascript"></script>
By adding an extension method to your project to extend Page:
public static class Extension_Methods
{
public static string ResolveClientUrlUnique(this System.Web.UI.Page oPg, string sRelPath)
{
string sFilePath = oPg.Server.MapPath(sRelPath);
string sLastDate = System.IO.File.GetLastWriteTime(sFilePath).ToString();
string sDateHashed = System.Text.RegularExpressions.Regex.Replace(sLastDate, "[^0-9]", "");
return oPg.ResolveClientUrl(sRelPath) + "?d=" + sDateHashed;
}
}
You can use SRI to break the browser cache. You only have to update your index.html file with the new SRI hash every time. When the browser loads the HTML and finds out the SRI hash on the HTML page didn't match that of the cached version of the resource, it will reload your resource from your servers. It also comes with a good side effect of bypassing cross-origin read blocking.
<script src="https://jessietessie.github.io/google-translate-token-generator/google_translate_token_generator.js" integrity="sha384-muTMBCWlaLhgTXLmflAEQVaaGwxYe1DYIf2fGdRkaAQeb4Usma/kqRWFWErr2BSi" crossorigin="anonymous"></script>

usemin, rev, less, source maps and IE8 selector count support

This is a source of concern and hard to solve whilst retaining the requirements.
Using usemin via grunt tasks to optimise a build of a complex and rather large application. The problem right now is that IE8 and IE9 are dropping CSS rule declarations from a single file being built on account of the ambiguous 4095 max rules limit.
currently, it works like so:
less builds one big file main-min.css in dist
source map added main-min.css.map
usemin process with rev to main-min.<hash>.css, main-min.<hash>.css.map
going forward, it needs:
less builds one big file main-min.css in dist
something like https://github.com/project-collins/grunt-csssplit converts to main-min-part1.css and main-min-part2.css (and so on). currently does not return names of new files, no support for source maps - but this is easy to patch and add or read from the FS
usemin to pickup the new split styles eg, from an assetDir and include all separately (not concatenated), which seems lacking in examples/workflow that try to create single files exclusively.
parts now rev'd
source maps? (acceptable to lose this)
any ideas / examples of such a setup appreciated. or alternative approaches.
If I understand your requirement correctly, this is the brief idea to solve your problem:
Steps:
1. Defined a pattern in your index.html. For instance:
<!--USE_MIN_BLOCKS-->
<!--END_BLOCK-->
2. Make a new replace task to replace above block with new usemin blocks dynamically (based on generated files of grunt-csssplit).
For instance:
replace: {
usemin: [{
match: /<!--CSS_USEMIN_BLOCKS-->[\S\s]+<!--END_BLOCK-->/i, replacement: function() {
//put your link tag here
linkTag += ' <!-- build:css css/' + cssFile + ' -->\n';
linkTag += ' <link rel="stylesheet" href="css/' + cssFile + '">\n';
linkTag += ' <!-- endbuild -->\n';
}
}]
}
3. Run the replace:usemin task before usemin task.

Emulate server-side rendering with Meteor

As we all know, Meteor's initial payload sent to the client comprises (in production) a concatenated javascript file containing the Meteor platform, packages, and all templates parsed into Meteor's reactive templating system. Server-side rendering, where the templates are rendered to HTML and sent to the client in the initial payload, is on its way but doesn't have an expected release date yet.
I'm looking for a way to "hack" or approximate server-side rendering given the available functionality in Meteor 0.8.x. Specifically, I want to:
enable the page to render its initial contents without first waiting for the several hundred KB Meteor platform javascript file to be downloaded and parsed.
alternatively, modify Meteor so it only sends the templates it needs to render the initial request in the javascript payload, and fetches the remaining templates once render is complete.
The use case is http://q42.com. I recognise Meteor isn't the best fit for static websites like this one but I want to try and see how far I can get anyway. Right now the Meteor platform JS file is over 600 KB in size (±200 KB gzipped) and I'd like to reduce this size if possible.
Note: I'm aware of and already using Arunoda's fast-render package, which is intended to send data with the initial payload. In this case I want to cut down on time-to-first-render by also getting the templates themselves down faster.
This is a little bit tricky. But there are some things you could do. This may not be the beeest way to do it but it could help you get started somehow.
Meteor is build with many packages as 'default', sometimes some are not needed. You can remove the standard-app-packages and add the packages (that you need and use manually) listed here: https://github.com/meteor/meteor/blob/devel/packages/standard-app-packages/package.js
To cut down the templates you would have to include the bare templates that you use and include the other template's separately and perhaps send down the Template information via a Collection, using a live observer handle to initiate the templates
You would have to 'render' the templates on the server side or store them manually in your collection using Spacebars.compile from the spacebars-compiler package which is a little tricky but you could have it done decently:
This should give you a rough idea, not sure how to get passed the 'eval' bit of it though:
HTML file in /private/template.html
<template name="test">
Hello {{name}}
</template>
JS file in /private/template.js
Template.test.name = function() { return "Bob" }
Server side code
var collection = new Meteor.Collection("templates");
var templateData = Assets.getText("template.html");
var templateJs = Assets.getText("template.js");
var compiled = Spacebars.compile(templateData).toString();
var jsData = templateJs;
collection.insert({templateName:"test", data: templateData, js: templateJs});
Client Side code
collection.find().observeChanges({
added: function(id, fields) {
var template = fields.data,
name = fields.name,
js = fields.js;
Template["name"] = UI.Component.extend({
kind: "name",
render: eval(template),
});
eval(js);
}
});
Then just subscribe to the collection asking for your template and it should exist. If you use iron-router I think (not sure) you could make the subscription wait before the template is rendered so you could have it work.
Again this is just a 'hacky' solution, one thing I personally don't like about it is the use of eval, but javascript needs to run somehow...
You could loop through files in a particular folder using fs = Npm.require('fs') to render each template too.
One alternative would be to inject a 'script' tag calling the compiled js template and template helpers to let the template exist.

Does minification affect JavaScript functionality?

I'm thinking of using bundling for my group's ASP.NET MVC3 project, and I can't break it cause I'm a junior dev.
Does JavaScript minification affect JavaScript function names - i.e. can I still call the functions that I minify by the same name from inline code? Also, does it ever effect how code behaves - or is JavaScript functionality and order fully preserved?
Bundling and Minification is not going to break your code by renaming your function names. The minification optimizes code through removing unnecessary whitespace, removing comments, and shortening variable names to one character.
Say you make this function:
function BigHonkingFunctionName(bigvariablename1, bigvariablename2) {
//I love this function
alert(bigvariablename1 + " " + bigvariablename2);
}
The minified result will be:
function BigHonkingFunctionName(n,t){alert(n+" "+t)}
So as you see, it won't impact how you call or use the function.
Reading on Bundling and Minification.
Normally Javascript minification does not change function names, and you can use them without worry. Javascript minification usually removes empty-spaces, new-line characters, shortens local variable names, shortens function parameter names.
Though you might get in trouble if your code uses eval statements which are referencing variables defined in its scope of access. Some minifier do not touch eval statements, which can be a bit problematic if the names of variables referenced by eval had been minified by the tool.
For example, following Javascript code block can be minified as following:
Source JS:
function eval_test(var_1, var_2) {
var_1 = "Updated var_1";
var_2 = "Updated var_2";
var a = eval("var_1 * var_2") + "<br>";
}
Minified JS:
function MyFunction(n,t){n="Updated var_1";t="Updated var_2";
var i=eval("var_1 * var_2")+"<br>"}
In this example the eval call will break after minification, because parameters var_1, var_2 of function eval_test are minified to n and t respectively. But the eval statement is still unchanged.
Still, some minfication tools do not minify parameter/variable names, in such a case eval statement will work perfectly fine. But keeping unminified parameter/variable names negatively affects the minification, because your code might not be as compressed/minified as it should.
You can try following online minification tools to test and verify minified output:
http://utilninja.com/Computing/JavascriptMinifier
https://javascript-minifier.com/
https://jscompress.com/
It is a valid concern. Probably depends on how your Javascript files are built, and now the bundler works. A lot of time, the bundlers do a great job of figuring everything out and leaving things in tact that need to be there.
A lot of bundlers do have configuration options to enable or disable options so you maybe able to configure the system to the exact way you want it, or if you run into problems.

How can I optimize the Microsoft AJAX Toolkit?

This is rather infuriating. I'm trying to optimize a very large site, and I'm at the step of reducing HTTP Requests. Microsoft is not cooperating. I have the following ScriptResources included. I'll try and grab a top-line for each to distinguish them
// Name: MicrosoftAjax.debug.js 53.5Kb
// Name: MicrosoftAjaxWebForms.debug.js 14Kb
AjaxControlToolkit.BoxSide = function() { 11.4Kb
/// Sys.UI.DomElement 958 Bytes!
// Sys.Timer 982 Bytes!
// IDropSource 6.5Kb
AjaxControlToolkit.FloatingBehavior = function(element) { 2.2Kb
AjaxControlToolkit.BehaviorBase = function(element) { 5.4Kb
AjaxControlToolkit.DynamicPopulateBehavior = function(element) { 2.9Kb
AjaxControlToolkit.BoxCorners = function() { 3.6Kb
AjaxControlToolkit.DropShadowBehavior = function(element) { 3.4Kb
AjaxControlToolkit.ModalPopupBehavior = function(element) { 5.5Kb
Come on! 12 Bloody javascript includes! Less than a KILOBYTE! Half the time to get the dang data is probably spent asking for it! ARGHHH!
Anyway, as you can see, I am annoyed. Is there some way I can roll these up, and combine them? Like into one request?
Just replace <asp:ScriptManager ... />
with <ajaxToolkit:ToolkitScriptManager> ... />
in your ASPX page and you're
done!
http://blogs.msdn.com/delay/archive/2007/06/11/script-combining-made-easy-overview-of-the-ajax-control-toolkit-s-toolkitscriptmanager.aspx
You can write a HTTPModule to grab all the the axd/js files from the response, combine them into one, and send them to the client's browser through a request to an HTTPHandler.
You can take a look at Mads Kristensen's site to know what I am talking about. There are a lot many articles/workarounds for problems like yours.
check this:
Fast ASP.NET web page loading by downloading multiple javascripts in batch
Also, one common mistake is setting <compilation debug=”true”/> in some of the sites I have seen. As per Scott Gu,
When <compilation debug=”false”/> is set, the WebResource.axd handler will automatically set a long cache policy on resources retrieved via it – so that the resource is only downloaded once to the client and cached there forever (it will also be cached on any intermediate proxy servers).
The question is how to minimize the overall requests to your server....
personally, i think its not a problem, if these js files are loaded ONCE.
because they should be cached by the client. maybe you want to investigate, why this does not happen.
and secondly there is a tag at the ScriptManager, that limits your js files....
maybe you want to look into the CompositeScript tag...
addditionally i would suggest looking into the LoadScriptsBevoreUI attribute and set it to false. then your content gets loaded bevore the javascripts.
Use CombineScripts=true inside your ToolkitScriptManager

Resources